Many devices have been proposed for stabilizing ships. Of the six degrees of freedom possessed by a ship, the stabilizing of ships in roll has most often been attempted since this motion is both directly related to passenger comfort, safety of operation of a working ship in the open sea and cargo security and in addition requires relatively low forces to achieve stabilization.
In some vessels movable fins have been employed to stabilize the ship in roll, however, these devices are complex requiring gyroscopic control and require extensive maintenance. Further these devices detract from the ships speed performance since they represent a considerable area protruding into the water. These characteristics together with the high cost involved make fin stabilizers unsuitable, particularly for smaller ships.
Tank stabilizers, particularly passive tank stabilizers, have obvious advantages in terms of simplicity in installation and maintenance. However, prior art tank stabilizers have either been suitable in configuration for use with many ships, produced excessive noise during operation, or have been insufficiently responsive to achieve sufficient stabilization. Further, prior art tank stabilizers have required the dedication of an excessively large portion of the ship's usable volume to the stabilizing device.
Thus it would be desirable if a simple tank stabilizer could be developed which had a high degree of flexibility in its placement and utilization and was more responsive to the rolling of the ship and achieved placement at the most effective location.